Abstract: Pillarless mining is a key research direction that has been continuously tackled in China’s coal mining field. Innovative achievements represented by gob-side entry retaining, “110/N00” mining methods, and backfill gob-side entry retaining (“111” mining method) have significantly promoted the development of this technology. Existing technologies mainly construct artificial “isolators” during mining to isolate goafs, striving to retain and maintain original mining gateways for reuse. However, in-depth investigations show that current technologies face four core challenges: mutual restrictions between longwall mining and “isolator” construction procedures, insufficient reliability of “isolators” which makes it difficult to effectively isolate goaf hazards, poor stability of reused gateways, and high maintenance costs. To address these issues, this study proposes a new integrated “excavation-backfill-retention” mining method based on existing achievements. The core of this method lies in replacing section coal pillars with backfill during excavation, which fundamentally solves the problem of process constraints and improves the stability of gob-side gateways. The study clarifies the technical principles and key difficulties of the new method, and innovatively plans a two-stage research approach: “realizing the new process with existing equipment” and “realizing the new process with innovative supporting equipment.” Considering the safety and implementation difficulty of on-site demonstration, three diversified technical paths are proposed: strip-type “excavation-backfill-retention”; stage-by-stage “excavation-backfill-retention”; extra-wide cross-section “excavation-backfill-retention.” The applicability of the diversified technical paths is analyzed by comparing with the traditional “121” mining method. The strong-weak composite backfill structure, material types, and their performance requirements are discussed. It is clarified that the section backfill must withstand the mining-induced impacts during primary mining and secondary mining. A mechanical model for the coordinated stability of backfill and surrounding rock is established, and the full-cycle bearing stages of the backfill from the initiation of hydration to the completion of secondary mining are divided. Numerical simulation is used to reveal the evolution characteristics of mining-induced stress in the section backfill: with the increase in its width, the vertical stress in the central area decreases significantly from 19 MPa to 13 MPa after secondary mining, eventually forming a typical “double hump” distribution characteristic. By investigating the actual production status of a coal mine in Yulin, an engineering demonstration plan for advancing 1 800 m with the stage-by-stage “excavation-backfill-retention” method is proposed. It is estimated that the demonstration project can achieve a benefit of 15.813 million yuan by saving gangue disposal costs and improving efficiency via coal pillar recovery, while forming two complete mining gateways, which has significant economic and comprehensive resource utilization value. The diversified technical paths of the “excavation-backfill-retention” method can flexibly realize the replacement of coal pillars with backfill of different widths, and the strong-weak composite backfill coordinated bearing system can simultaneously dispose of coal-based solid waste. This study provides new ideas for breaking through the technical bottlenecks of pillarless mining and realizing the resource utilization of solid waste in mining areas.